Which LOD levels do most use?

Although I have building cars in 3DC for several years, I have just just now decided to upload my first one. I just sent a flatcar to a person for a pre-upload test run and he commented that it performed great except that ‘the LODs are set up so that anything more than 3-4 cars back from the engine has the parts disappearing in the 4-key view.’-�

I used the MS Train Simulator Wizard plug-in for this car and selected the Standard Distance Levels option but left the Retain Sub-Objects unchecked.

I assume this is an export LOD option problem so I am asking which LOD options do most use when exporting with this plug-in, and why? Have studied the MSTS Distance Levels tutorial but am not sure which option to use.

Any advice appreciated, Bill